[seanos]

One obvious improvement would be to replace the warning "Stall!" with "Stall! Stall protection disengaged!" when flying in alternative mode. Even better might be "Stall! Push stick forward!" when a stall is detected and the pilot is simultaneously pulling back on the stick.

[gcp]

I don't think more complex aural warnings would have accomplished anything [1]. (Edit) This guy basically had his brain disengaged due to panic and was useless at that point. The tragedy is that the other pilots couldn't prevent it.

The plane also warned them aurally that they were giving conflicting inputs. None of them "understood" it, in the sense that they thought about what that must have meant.

[1] Though, having the stall alarm go off when the stall was too deep is very, very weird and may have contributed to the issue.

(Edit: I initially said that pilots are deeply trained to use stick down to recover from a stall - but apparently this isn't really true for commercial pilots who are trained to avoid height loss when near a stall.)

[seanos]

The crash report says that the second pilot and pilot (when he arrived) were both unaware that the other copilot was pulling back on his stick. E.g. at one point the other copilot had his stick forward (causing an averaging of the two inputs resulting in nose still up) and right before the crash when the copilot replies "But I've had my stick back all the time!" the other two get a shock. The warning "Stall! Push stick forward!" would therefore have saved the day, even if the copilot pulling back ignored it (and it seems he thought he was doing the right thing by pulling back, so the explicit advice "Push stick forward!" might have helped in his mental state), the other two would realise he was contravening normal response.

[gcp]

The warning "Stall! Push stick forward!" would therefore have saved the day...the other two would realise he was contravening normal response.

They already got this warning through a "DUAL INPUT" alarm, among all the other alarms that went off. When the pilots panic, adding warning after warning is useless, they won't hear them anyway, let alone the nuance in the stall warning. See for example: http://msquair.wordpress.com/2011/09/16/pilots-in-the-loop-a...

"it turns out that in the circumstances identified as triggering instinctive responses the value of such alerts is degraded due to the inevitable attentional tunnelling that operators experience in high stress situations."

Hell, to put it in a software perspective: popping up warning dialogs for your users is pointless, as they click them away anyway without reading.

Tactile feedback, such as the stick itself moving or resisting input, is not possible to ignore, so it's not surprising the pilots would have preferred this.

Note that even in alternate law the plane actually attempts to correct the stall by itself, so its hard to see how giving an audible warning would have gotten him to realize he was doing things the wrong way around. He was already actively working against the correction. http://www.airbusdriver.net/airbus_fltlaws.htm

"System introduces a progressive nose down command which attempts to prevent the speed from decaying further. This command CAN be overridden by sidestick input."

[seanos]

The dual input warning doesn't inform specifically that copilot 1 is pulling back on the stick. It's clear from the report that was the problem, copilot 1 was pulling back the whole time and nobody realised.

I'm not suggesting adding "warning after warning" but an improvement to the existing warning, after all, when the plane is heading for the ground the warning is "Pull Up! Pull Up!" not "Ground!". If you want a software analogy, "Stall" is akin to "Error: Read Failure" and "Stall! Push Stick Forward!" akin to "Read Failure: Insert Disk".

Anyway it's a cheap to implement improvement and could save lives.

[gcp]

The dual input warning doesn't inform specifically that copilot 1 is pulling back on the stick. It's clear from the report that was the problem, copilot 1 was pulling back the whole time and nobody realised.

There is only 1 pilot at a time that is supposed to fly the plane, so the warning in itself indicates that they are in serious conflict and should clarify who is flying and what to do. They payed no attention to it. Again, hard to believe adding more audible warnings would improve that, rather than make it worse.

At some point they are discussing whether they are ascending or descending, while the stall alarm is blaring throughout. I don't think anyone will consider making the stall alarm go "Stall! Losing attitude!".

"Pull Up! Pull Up!" not "Ground!"

Notice how in this case they did get that warning...and it further doomed them, because Bonin started pulling back again.

[seanos]

"At some point they are discussing whether they are ascending or descending, while the stall alarm is blaring throughout. I don't think anyone will consider making the stall alarm go "Stall! Losing attitude!"."

Yep, but your missing the fact that they didn't believe it was actually stalled or about to stall. They thought that was impossible since normally the fly-by-wire protects against it, so that warning can safely be ignored. That is why they ignored it. It's kind of like the boy that cried wolf. Normally, the warning can be ignored and so when it started sounding when it really mattered, they ignored it. Maybe interlacing "Stall! Stall Protection Disengaged!" (when in alt mode) and "Stall! Push Stick Forward!" (when stick back) is the ideal solution.